A scan design method is employed as a method for facilitating a test for a large-scaled LSI. When a scan composition is performed with a design of facilitating test (“DFT”) tool on the basis of a net list before the scan composition, scan chain reorder information is generated as an interface to a location and wiring tool. The location and wiring tool performs a reordering of a scan chain on the basis of the scan chain reorder information.
In the conventional scan chain reorder information, however, information on a start point and an end point for a reordering with respect to the scan chain is not set. In addition, information on an order of cells on the scan chain, a unique name and a terminal name of each cell is not set. Further, information on a clock domain or a polarity of a scan flip-flop on the scan chain is not set. Furthermore, information which prohibits the reordering with respect to the cells in a software macro cell is not set either.
Therefore, when the reordering is performed on the basis of the conventional scan chain reorder information, since the information on the start point and the end point for the reordering does not exist, there is a problem that it is difficult to search a reorder object in the scan chain. Further, since the unique name of a cell on the scan chain is not known, there is a problem that a penetration of cell occurs due to an overlook of cell by a designer. Furthermore, since the information on the terminal name of a cell does not exist, there is a problem that, when a connection between a scan-in terminal (hereinafter, referred to as SI terminal) and a scan-out terminal (hereinafter, referred to as SO terminal) is erroneously conducted, it is impossible to determine the fact as an error.
Further, since the information on the clock domain and the polarity does not exist, the reordering is performed without considering the clock domain and the polarity, there is a problem that the penetration of data occurs or that a normal value cannot be latched. Further, since reorder prohibition information does not exist, there is a problem that, when the scan flip-flop is configured with a software macro cell structured of a combination of a selector and the scan flip-flop, the cells in the software macro cell are also reordered so that logic is changed.